This invention relates to improved apparatus and to an improved method for producing a pressed glass article. In particular, the apparatus includes means for causing a gas which is a mixture of at least one alkane and at least one unsaturated aliphatic hydrocarbon to flow from a manifold around the exterior of a plunger, means for igniting the gas so that it deposits a substantially invisible lubricious coating on the plunger., and means for advancing the plunger into a gob of molten glass in a mold. Preferably the gas which is caused to flow from the manifold is a mixture of from 40 to 70 parts by volume of "C-53 gas" (subsequently defined) and 60 to 30 parts by volume of methane.